Methods for treating clogged underground sewage drain systems



United States Patent O" METHODS FOR TREATING CLOGGED UNDER- GROUNDSEWAGE DRAIN SYSTEMS George R. Hewey, Mentone, Calif.

Application August 17, 1953, Serial No. 374,590

16 Claims. (Cl. 210-6) This invention relates to improved methods forcleaning 'out or reconditioning clogged sewage draining systems, such ascesspools, -drain pits, or leach lines, each of which includes anunderground chamber or pipe line into which sewage is fed and from,which the sewage drains into a porous earth formation. In certainrespects, the present method may be considered improvements on treatingmethods disclosed in my copending application No. 274,550, tiled March3, 1952, on Method for Cleaning Cesspools.

After an underground sewage draining system has been in use for a periodof time, it frequently accumulates a mass of dense clogging materialalong the walls of the underground chamber and within the communicatinginitially porous drain formation. terial acts to clog the system andthereby prevent proper drainage from the chamber. The conventionalmethod of cleaning such a system has been to break up the accumulationwithin the chamber and then pump it and the water in the chamberupwardly to the surface of the eart and into a tank for disposal.

The present invention has to do with an improved treating System whichcompletely eliminates the necessity for thus withdrawing any of thecontents from the underground chamber, and at the same timereestablishes the original lateral and bottom drainage. Specically thisis achieved by so treating the accumulated clogging material within thechamber and formation as to disintegrate and decompose it to a statecapable of passage through the interstices of the formation to theoutlying formation. The decomposed material may then be drained rathercompletely from the chamber and formation, leaving the systemsubstantially as open as it originally was.

The decomposition of the clogging material may be effected largely bycontacting the material with a decomposing acid, preferably sulfuric orphosphoric acid, having the effect -of solubilizing the material. YTheeifect of the acid may be enhanced by also contacting the material withan ammonia reagent, desirably an aqueous solution of ammonium hydroxide.It is also found that the addition of a strong oxidizing agent to thesystem, desirably potassium permanganate, aids in completelydecomposingvorV burning the accumulated clogging material. A finalchemical which has been found useful is saponin, which may be added inextract form or as yuccaV plant, and acts to prevent the formation of anew crust land keep the formation soft and openafter an acid treatment.The acid and other chemicals are in part filled directly into thedrainage chamber, and in part injected into the porous formation atlocations spaced from the chamber. The chemicals fed to the formationmay be applied by drilling anumber of holes into the formation,desirably from both the interior and exterior of the chamber, andfilling the chemicals into those holes. In accordance with thedisclosure of my copending application Ser. No. 274,- 550, thesedrilling operations may be performed 'by a hydraulic nozzle, acting todischarge a high veiocity flow Vofliquid which progressivelypenetratesinto the Yforma- This accumulated ma- 2,768,949 Patented Oct. 30, 1956ICC tion. The chemicals may then be forced into the formation throughthe same nozzle after it has penetrated to a desired depth. Such anozzle may also be employed for initially breaking up the accumulatedclogging ma-l terial within the chamber or in the porous formation, bydirecting high velocity liquid streams into the material or formation ata number of different locations about the chamber walls.

The above and other features 'and objects of the present invention willbe better understood from the following detailed description of thetypical embodiments illustrated in the accompanying drawing, in which:

Fig. l is a vertical section through a ucesspool being cleaned by thepresent method; (l A .i

Fig. 2 is an enlarged fragmentary section throughthe drilling `and fluidinjecting nozzle shown in Fig. l; v

Fig. 3 is a vertical section through a septic tank and leach line systembeing cleaned by the present method; and

Fig. 4 is a vertical section taken on line 4 4 of Fig. 3.

Referring rst to Fig. 1, I have there shown a conventional cesspoolsystem for sewage disposal, including the usual cesspool chamber 10 intowhich sewage is fed through line 11. At its bottom, chamber 10communicates with a stream of gravel or other initially porous formation12, through which liquid from within charnber 10 drains into theoutlying formation. Spaced above formation 12, there may typically be asecond porous formation 13, affording a second liquid outlet Afromchamber 10. In some cases, the lower drainage layer 12 is not present,in which case the chamber 10 is usually referred to as a drain pit,rather than a cesspool. Where the term cesspool i-s used in the claims,it is to be considered as including such a drain pit arrangement. Afterthe system of Fig. l has been in use for a considerable period of time,a dense hardened coating of clogging material 14 accumulates along thechamber bottom and side walls as shown, closing oif the drainage ofwater and other materials from the chamber into the porous formations.This clogging material `also accumulates within and closes the pores ofthe various formations adjacent the bottom and sides of chamber 10. Thepurpose of the present invention is to remove the accumulated materialfrom within chamber 10 and the surrounding formation, to again open upthe original drainage paths from the chamber.

For use in cleaning the accumulated material from the system, I employan elongated pipe 16, typically formed of a number of standsinterconnected at joints 17, and carrying at its lower end a nozzle 18adapted to hydraulically drill into the accumulated material or earthformation, and then inject a treating liquid into the material orformation. Pipe 16 is connected atits upper end by a hose 19 to avehicle carried pump 20, adapted to force liquid under pressuredownwardly from the pipe and to nozzle 18. The suction side of pump 20may be con- Ynected selectively to either of two chemical supply tanks21 or 22, or to a source of water.

Nozzle 18 is tubular (see Fig. 2) and has a lower tapered or pointed end23 adapted to penetrate into the earth. Spaced a short distance ab-oveits lowermost end, the tapered lower portion 23 of 'nozzle 18 has anumber of circularly spaced liquid outlet openings 24, through whichhigh velocity streams of 'liquid jet from the nozzle. Openings 24 extendangularly as shown, to direct the liquid streams at an angle laterallyand forwardly,l in a manner such that the ejection `of liquid from thenozzle acts to hydraulically drill a hole in the earth through which thenozzle and pipe 16 may penetrate. In cleaning a cesspool with theapparatus of Figs. l and 2, pipe 16 and nozzle 18 are lowered into theIcesspool chamber 10 through an upper access opening 25, and pump Z0 isthen cau-sed to feed water under high pressure, say between about 300and 600 lbs. per square inch, to nozzle 18. This high pressure water is'of course emitted through nozzle openings 24 as a series of circularlyspaced high velocity streams. Pipe 16 may be manipulated to cause thenozzle to penetrate the accumulated material 14 within chamber 10, andthe water streams then act to break up or disintegrate the coatingmaterial into a large number of particles. When this preliminaryprocedure is used, the nozzle is injected into coating 14 at enoughdifferent places across the bottom and sides of the chamber tocompletely break up the inner coating of clogging material. Nozzle 16 isthen advanced ydownwardly within bottom formation 12 at a number ofdifferent locations, to hydraulically `drill into the formation andbreak it up.

After the above steps have been taken, nozzle 18 is cause tohydraulically drill into or penetrate the formation beneath chamber 10to a depth of about 6 to l0 feetbelow the bottom of the chamber, thehigh pressure water discharge at the nozzle of course being maintainedthroughout the drilling process. With the nozzle then located 6 'to lOfeet below the bottom :of the chamber and within the porous formation12, the suction side of pump 20'is changed .over to draw from tank 21,rather than the water source. This tank contains a supply of a strongacid, preferably selected from the group consisting of phosphoric acidand sulfuric acid, and for best results the latter. Between about and l0gallons of this acid, typically of a concentration of 66 B., aredischarged through the nozzle into the surrounding formation at apressure, between about 60 and 8() lbs. per square inch. The nozzle isthen withdrawn and caused to drill into the formation 12 at a s-econdand different location, and again desirably to a depth between about 6and 10 feet below the chamber. A second charge of acid is fed into theformation at the second penetrated location. This process is repeated atseveral different locations spaced across the entire area of the chamberbottom, to distribute the acid about the entire lower formation. Thisacid acts to decompose or solubilize the clogging material withinformation 12, to a condition in which the material will flow freely fromthe formation into the outlying earth formation.

To further the disintegration of the coating material 14 within thechamber, and to decompose and solubilize that material, i add to thebody of water 26 within the chamber, preferably after all of the abovesteps have been completed, sufiicient acid of the above discussed typeand concentration to amount to approximately 1 to 2 gallons for each 100gallons of capacity 4of chamber 10. The decomposition of some of thematerial in coating 14 may be enhanced by also adding to the chambercontents a strong oxidizing agent, such as potassium permanganate,nitric acid, or the like. For best results the oxidizing agent ispotassium permanganate, about 5 to 10 lbs. of this chemical typicallybeing employed. The oxidizing chemical preferably is placed on top ofwhatever residue may remain along the bottom of the chamber. As a finalstep in the internal treatment of chamber a quantity of saponin is addedinto the cesspool chamber, either as about l gallon of saponin extract,or about 25 lbs. of yucca plant, to aid in leaching out any cloggingmaterial not removed by the other chemicals.

In the above internal treating system, the decomposition of cloggingmaterial is of course effected in large part by the acid reagent. Inmany instances, it has been found that the utilization 4of an ammoniareagent in addition to the acid results in more rapid and completedecomposition of the clogging material. The preferred reagent fior thispurpose is an aqueous solution of ammonium hydroxide, e. g. l gallon ofammonium hydroxide to 300 gallons of water. This ammonium hydroxide maybe ejected into formation 12 at locations deep within the formation inthe manner discussed in connection with the acid ejection, and/or mixedwith the water in chamber 10. Preferably, the chamber and formation arefirst treated with ammonium hydroxide, and then with acid, the formerbeing especially helpful in initially breaking up the clogging material,while the latter is most effective as a decomposing or solubilizingagent. In some cases, the ammonium hydroxide solution rather than watermay be fed to nozzle 18 during drilling, so that the disintegratingeffect of the high velocity liquid streams may be supplemented by thechemical action of the ammonium hydroxide.

After the cesspool chamber has been internally treated, nozzle 18 andpipe 16 are again connected to a high pressure source of water, andutilized to drill a number of vertical holes 27 downwardly from thesurface of the earth at a series of locations spaced outwardly from thechamber, and spaced circularly about the chamber. Into these holes 27,which may extend downwardly to approximately the bottom of the cesspoolchamber, I pour sufficient sulfuric or phosphoric acid to fill theholes, usually about l to 2 gallons in each hole. Additional holes 127may be drilled angularly downwardly from the surface of the earth intothe sides of the chamber and through the accumulation 14 therein. Theseangular holes allow chemicals from within the chamber to ow to the backside of accumulation 14, and thus facilitate its removal from thechamber walls. V

Prior to the filling of acid into holes 27, I may fill an aqueoussolution of ammonium hydroxide into the holes. Also, the above discussedoxidizing agent and saponin may be filled into the holes, to enhance theeffect of the acid and ammonium hydroxide in thoroughly disintegratingand decomposing the clogging material accumulated with the side wallformation.

The discussed internal and external treatment of the cesspoolV of Fig. lacts to thoroughly decompose the major portion, and usuallysubstantially all, of the clogging material within chamber 10 and theadjacent formation. This decomposed or solubilized material is able topass through the interstices of formation 12 and 13 into the outlyingformation with the water from the chamber. The chamber is thuscompletely drained and placed in substantially its original freedraining condition.

Figs. 3 and 4 illustrate a variational form of sewage draining systemincluding an underground septic tank 28, from which sewage flows througha horizontally elongated underground leach line 30. Line 30 may beformed of a number of sections loosely connected at joints 31, andcontaining wall apertures 32 along the entire length of the line throughwhich water from within the line discharges into a surrounding gravel orother porous formation 33. In this system of Figs. 3 and 4, leach lineSi! may be considered to form an underground drain chamber correspondingessentially to chamber 10 of Fig. l. After an extended period of use,dense and hardened clogging material accumulates within pipe 30 and itsapertures, and within the formation or gravel fill 33, acting to closeoff the system against proper drainage into the outlying formation.

For cleaning out the system of Figs. 3 and 4, I first make a hole in theleach line at a location 34 near the septic tank, and connect a hose 35into the line at that point. An ammonia reagent, preferably an aqueoussolution of ammonium hydroxide, is then forced through hose 35 into line30 under high pressure, typically about 400 lbs. per square inch. Thisoperation is repeated at 50 ft. intervals along the length of line 30and to its end.

Next, sulfuric or phosphoric acid, preferably the former and having aconcentration of about 66 B., is ejected under pressure (e. g. aboutlbs. per square inch) into line 3 0 through hose 35 at 50 footspaced'locations in the same manner in which the amonia reagent wasintroduced.

After such internal treatment of line 30, a nozzle 18 and line 16corresponding to those shown in Fig. 1 are utilized to hydraulicallydrill downwardly into the earth vformation adjacent line 30. A pair ofholes-36 at opposite sides of line 30 may be drilled in this manner ateach 3 foot interval along the length of line 30. These holes 36 mayextend angularly downwardly as seen in Fig. 4, through the gravel ll 33and to a depth about 8 or 10 feet below the gravel lill. At thelocations of each pair of diagonal holes 36, a third hole 37 may bedrilled directly downwardly above line 30, terminating in the gravellill 33 above the line.

Into each of the holes 36 and 37 drilled in the above manner, I pouracid of the type andL concentration previously discussed, in quantitiessufficient to lill the holes. While this acid treatment isV generallyfound sufficient for the purpose, I may in certain circumstances precedethe use of acid by the filling of an ammonium hydroxide solution intothe holes. Also, if desired, the oxidizing agent and/or saponin referredto in connection with Figs. l and 2 may be ejected into pipe 30internally or filled into holes 36 and 37.

The described treatment of the Figs, 3 and 4 system acts to disintegrateand decompose or solubilize the clogging material which has accumulatedwithin line 30 and gravel fill 33, as well as the adjacent earthformation. The accumulated material is then able to flow with the othercontents of line 30 through gravel 33 into the outlying formation. Thisof course returns the septic tank and leach line system to substantiallyits original free draining condition. After this treatment, the owner ofthe system is encouraged to feed saponin at regular intervals throughthe system, typically about l gallon of saponin extract per month, as anaid in maintaining the system in its cleaned condition.

In the above described treating methods, to accomplish sulfation orsulfonation of materials in the regions being treated, I may in certaininstances use sulfur trioxide instead of and as the equivalent ofsulfuric acid, although the latter is preferred.

I claim:

l. The method of treating an underground drain system including a watercontaining chamber and a porous formation initially communicatingtherewith to remove dense clogging material from the walls of thechamber and within the formation; said method includingdisintegratingan-d decomposing said clogging material in the chamber toa condition capable of passage through the interstices of said porousformation, disintegrating and decomposing the clogging material in saidformation by penetrating and injecting within the formation apressurized acidic uid stream -to open a drainage path therethrough, anddraining the contents of said chamber including said clogging materialthrough the porous formation and into the outlying formation.

2. The method recited in claim 1, in which the disinteeected byincluding in said stream ammonium hydroxide, sulfuric acid and potassiumpermanganate.

8. The method of treating an underground sewage drain system including awater containing chamber and a porous formation initially communicatingtherewith to remove 'dense sewage clogging material from the chamber andfrom within the porous formation preventing proper drainage from thechamber, said method including, acid treating and disintegrating saidmaterial in the chamber, drilling a hole into the earth from 'a locationat the outside of said chamber and into said porous formation, andintroducing into said hole a reagent acting to break up said cloggingmaterial and thereby open the porous formation for drainage from thechamber.

9. The method of treating an underground sewage drain system including awater containing chamber and a porous formation communicating therewithto remove dense sewage clogging material from the walls of the chamberand within the formation; said method including disintegrating saidmaterialv within the chamber, drilling a plurality of holes into theearth from locations at the outside of said chamber and into said porousformation, introducing an acid selected from the group consisting ofsulfuric acid 'and phosphoric acid into said holes and into said chamberto thereby disintegrate and decompose said clogging material, and thendraining the contents of said chamber including said clogging materialthrough the porous formation and into the outlying formation.

10. The method as recited in claim 9, in which said acid is sulfuricacid, said method including introducing an aqueous solution of ammoniumhydroxide into said f holes and chamber prior to introducing acidtherein to gration and decomposition of said clogging material iseffected by fan acid in said stream selected from the group consistingof sulfuric acid and phosphoric acid.

3. The method recited in claim l, in which the disintegration :anddecomposition of saidclogging material is effected by sulfuric acid linsaid stream.

4. The method recited in claim l, in which the disintegration anddecomposition of said clogging material is effected by including in saidstream an :ammonia reagent and an acid selected from the groupconsisting of sulfuric acid and phosphoric acid.

5. The method recited in claiml, in which the disintegration anddecomposition of said clogging material is effected by ammoniumhydroxide and sulfuric acid in said stream.

6. The method recited in claim 1, in which the disintegration anddecomposition of said clogging material is 7. The method recited inclaim l, in which the disintcgration and decomposition of said cloggingmaterial is facilitate the disintegration of said material.

1l. The method of treating a water-containing cesspool chamber andporous formation initially communicating therewith to remove denseaccumulated material sewage on the walls of the chamber and within theformation preventing proper drainage from the chamber; that includesacid treating and disintegrating and decomposing said clogging materialin the chamber to a condition capable of passage through the intersticesof said porous formation, independently penetrating said porousformation and introducing thereinto at a location spaced from saidchamber an acid selected from the group consisting of sulfuric acid andphosphoric acid acting to clean the porous formation, and then drainingthe contents of said chamber including said clogging material throughthe porous formation and into the outlying formation.

l2. The method of` treating a water-containing cesspool chamber asrecited in claim 11, in which said disintegration and decompositionwithin the chamber is effected by penetrating said clogging material onthe walls of the chamber at different locations and jetting thereinto ayhigh velocity liquid stream, :and introducing into the-chamber water anacid selected from the group consisting of sulfuric acid and phospho-ricacid acting to solubilize the clogging material.

13. The method recited in claim ll, including jetting into said porous'formation at a plurality of locations outside of said chamber an aqueousammonia stream for facilitating the disintegration of the cloggingmaterial.

14. The method of treating la Water-containing cesspool chamber andporous formation initially communicating therewith to remove denseaccumulated Vmaterial on the walls of the chamber and within theformation preventingV proper drainage from the chamber; that includesVpenetrating said clogging material onthe chamber walls at differentlocations and jetting thereinto'a high Vvelocity liquid stream .actingto break up the material,vr

adding ammonium Ahydroxide and sulfuric'v acid to the water in saidchamber in quantities acting to decompose said material in theV chambertoa condition' capable of passage through the interstices of saidformation, penetrating said porous formation 'and jetting thereintounder pressure at a plurality of locations spaced from the chamber highvelocity streams yof ammonium Vhydroxide and sulfuric acid to clean theporous formation, and then draining the contents of said chamberincluding said clogging material through the porous formation and intothe outlying formation.

15. The method as recited in claim 14, including adding potassiumpermanganate into said chamber to aid in decomposing said cloggingmaterial.

16. The method of treating a perforated leach line embedded within aporous formation to remove dense accumulated clogging material fromWithin the line and in said formation; that includes injecting an acidselected from the group consisting of sulfuric acid and phosphoric acidunder pressure into said line to solubilize the clog- 8 `ging materialtherein, 'd-rillingholes into said porous formation at the outside ofsaid line, filling acid into said .holes to Aclean the forma-tion, anddraining the contents of said line including said clogging materialthrough said porous formation into the outlying formation.

References Cited in the le of this patent UNITED STATES PATENTS

1. THE METHOD OF TREATING AN UNDERGROUND DRAIN SYSTEM INCLUDING A WATERCONTAINING CHAMBER AND A POROUS FORMATION INITIALLY COMMUNICATINGTHEREWITH TO REMOVE DENSE CLOGGING MATERIAL FROM THE WALLS OF THECHAMBER AND WITHIN THE FORMATION; SAID METHOD INCLUDING DISINTEGRATINGAND DECOMPOSING SAID CLOGGING MATERIAL IN THE CHAMBER TO A CONDITIONCAPABLE PASSAGE THROUGH THE INTERSTICES OF SAID POROUS FORMATION,DISINTEGRATING AND DECOMPOSING THE CLOGGING MATERIAL IN SAID FORMATIONBY PENETRATING AND INJECTING WITHIN THE FORMATION A PRESSURIZED ACIDICFLUID STREAM TO OPEN A DRAINAGE PATH THERETHROUGH, AND DRAINING THECONTENTS OF SAID CHAMBER INCLUDING SAID CLOGGING MATERIAL THROUGH THEPOROUS FORMATION AND INTO THE OUTLYING FORMATION.